body {
    font-size: 13px;
}
.value_px {
    font-size: 32px;
}
.value_em {
    font-size: 2em;
}
.value_rem {
    font-size: 2rem;
}
.color_name {
    color: red;
}
.color_hex {
    color: #ff6700;
}
.color_rgb {
    color: rgb(0, 255, 0);
}
.img_url {
    background-image: url(../html_base/原图.jpg);
    width: 681px;
    height: 1024px;
}
.font_demo {
    font-family: "宋体", sans-serif;
    font-size: 20px;
    font-style: italic;
    font-weight: bold;
}
.text_demo {
    font-size: 3em;
    border: 1px solid black;
    width: 30rem;
    height: 10rem;
    /* margin: 0 auto; */
    text-align: center;
    line-height: 10rem;
}
ul {
    font-size: 2rem;
}
.list-demo {
    list-style: square;
    /* list-style: none; */
    /* list-style-image: url(../html_base/qrcode.png); */
    
}

.bg-box {
    border: 3px solid black;
    width: 50rem;
    height: 40rem;
}
.bg-demo1 {
    background-color: #ff6700;
}
.bg-demo2 {
    background-image: url(../html_base/baidu_log.png);
}
.bg-demo3 {
    background-image: url(../html_base/baidu_log.png);
    background-repeat: repeat-x;
}
.bg-demo4 {
    background-image: url(../html_base/baidu_log.png);
    background-repeat: no-repeat;
    background-position: center center;
}
.bg-demo5 {
    background-image: url(../html_base/baidu_log.png);
    background-repeat: no-repeat;
    background-position: top right;
    background-attachment: scroll;
}
.bg-demo6 {
    background: skyblue url(../html_base/baidu_log.png) no-repeat top right fixed;
}
.table-demo caption {
    font-size: 3rem;
}
.table-demo {
    font-size: 2rem;
    border: 1px solid black;
    width: 70%;
    margin: 0 auto;
    table-layout: fixed;
    border-collapse: collapse;
}
.table-demo th,
.table-demo td {
    border: 1px solid black;
    text-align: center;
}
.table-demo thead {
    background-color: rgb(6, 6, 6);
    color: white;
}
.table-demo tbody tr:hover {
    background-color: #ff6700;
    cursor: pointer;
}
.table-demo tfoot td {
    text-align: right;
    padding-right: 60px;
}

.form-demo {
    font-size: 20px;
    border: 1px solid black;
    background: white;
    width: 35rem;
    height: 25rem;
    text-align: center;
}
.form-demo input[type="text"],
.form-demo input[type="password"] {
    border-top: 0;
    border-left: 0;
    border-right: 0;
    border: 1px solid black;
    width: 300px;
    height: 40px;
    padding-left: 10px;
}
.form-demo i {
    font-size: 35px;
}
.form-demo [type="submit"] {
    width: 100px;
    height: 30px;
    /* background-color: #ff6700; */
    border: 1px solid black;
    border-radius: 15px;
    text-align: center;
}
.form-demo [type="submit"]:hover {
    background-color: #ff6700;
}